Balanced modulating reflectors



May 22, 1928. 1,670,352

J. H. HAMMOND. JR

BALANCED MODULATING REFLECTORS Filed Dec. 24, 1925 40 1 2541 IIIIIIIIIYIIIIXI A, A 2r?" QIIJI Patented May 22, 1928.

' UNITED STATES JOHN HAYS HAMMOND, JR., 0]? GLOUCESTER, MASSACHUSETTS.

BALANCED MODULATING REFLECTORS.

Application filed December 24, 1925. Serial No. 77,518.

This invention relates to musical instruments of the percussive type and more especially to pianofortes.

-Broadly Stated it; is the principal object of the present invention to provide improved means for controlling damped musical sounds.

According to one feature of the invention a plurality of groups of modulating reflectors are provided and the reflectors of each group are balanced with respect to each other so as to be operated with very slight exertion on the part of the operator.

Other objects will appear from the following description taken in connection with the accompanying drawings in which I Figure 1 is a front elevation partly in section of a grand piano having features of the invention; and

Figure 2 is a bottom plan view of the piano of Figure 1'.

Like reference characters refer to like parts in the several figures of the drawings.

In the following description and claims, parts will be identified by specific names for convenience of expression but they are intended to be as generic in their application to similar parts or the equivalent construction as'the art will permit.

Referring to the drawings, there is shown so much of a grand piano as is necessary to an understanding of the present inven tion and having applied thereto the features hereinbefore mentioned. In the embodiment illustrated'the piano 10 includes a plurality of tuned stringssuch as 11 mounted in a frame 12. For vibrating the strings of each of the notes of the musical scale by percussion there is provided a suitable hammer action such as 13 operatively connected to each one of the keys 14 of the manual of the piano.

The strings are positioned within a casing 15 divided into two interior resonating chambers by means of a sounding board 16. A plurality of pedals such as 17, 18, 19 is mounted in a pedal block 20 below the easing 15. The pedals are operatively connected with rods 21, 22, 23 respectively. The two right hand rods 22, 23 are connected to the usual sustenuto and loud pedal action of the piano which being well known in the art need not be more fully described.

The upper end of the left hand rod 21 en gages one arm of a bell crank lever 26 which is pivoted as at 27 and is maintained in the position illustrated in Figure l by means of a spring such as a leaf spring 28. The other end of the bell crank lever 26 is pivotally connected to one end of a link 30, the other end of which is connected to an arm 31, se cured to a vertical shaft 32. The shaft 32 is mounted in bearings 33, 34: and is provided with a collar 35 to maintain the shaft in fixed longitudinal position with respect to its bearings. An arm 36 is affixed to the shaft below the lower wall of the casing 15 and is pivotally connected at its outer end to a link 37 extending to a reciprocating connecting rod 38. Similarly there is secured to the shaft 32 near the upper wall of the casing 15 an arm 39, the outer end of which is pivotally connected by means of a connecting link ll) to an upper reciprocating rod 11.

The casing 15 is provided with oppositely disposed controllable apertures as at 50, 51 (see Fig. 1). There is mounted in the upper aperture 50, a series of reflectors as at 53, serving to control the emission of sound. Each reflector 53 is preferably in the form of an elongated flat member having bevelled lateral edges and pivoted at one of its edges. Each reflector is provided on its inner surface with a layer 5 1 of sound reflecting material which may be of sheet metal having a smooth surface such as sheet aluminum, and is provided on its outer face with an arm 55. The outer ends of the arms 55 of the upper series of reflectors are pivotally connected to the upper connecting rod 11.

111 the lower aperture 51 of the casing there is mounted a second series of reflectors to control the emission of sound. The construction of the lower group is similar to that of the upper group and includes for each reflector a sound reflecting layer on the inner face which in this case is the upper face. The outer ends of the arms 55 of the reflectors of the lower group are pivotally connected to the lower connecting rod 38. The reflectors of the lower group are pivotally mounted on one edge, and in the embodiment illustrated the two series of reflectors are so arranged as to reflect the sound towards the strings tuned to the treble notes of the scale, and so that as the force of gravity is exerted upon the reflectors of one of the groups to open them, for example, it also acts on those of the other group to tend to close them. The reflectors of the two groups n being similarinnuinbe'r and lflCOllStIillCtlOll,

their weights are thus substantially bal anced.

Surrounding the apertures the casing ineludes an upper iva'll 56 and a loiver wall 57 skirting the respective apertures and having edges bevelled to conform to the edges of the contiguous reflector The alls 56, 57 and the intermediate boundary walls of the casing 15 are provided ont he interior with a layer of sound reflecting material which may be of sheet metal having a smooth surface such as sheetjaluminum or the li;ke. There are thus formed two resonating chambers, one designated by the reference character 60,, extending between the upper series ofreflectors and the sounding board 15 and the second resonating chamber designated 61 extending, between the so inding board 16 and the lower group oft reflectors. v

It W lll be seen that the arrangement is such that the weight or" the several reflectors the lower group counterbalances the eight of theupper group of reflectors so that the reflectors canbe moved easily.

I In operation, the manual of thepiano is employed by the musician in the usual way to cause vibrationof the strings 11 in cordance with the musicheingplayed In o'rderdt'o produce a desfired efieet let it be 'assumedthat it is desired to sustain some ofthe notes of the music. Accordingly the pedal 17 is lield down and thus the rod 21 'is moved upwardly sons to rotate the bell crank lever 26 in a counter clockwise direction as seen, in Figure 1. The connecting link 30 a nd the connecting rods 38 and 4:1 are moved to the rightand thus the reflecterse?) of the upper group of refiectors are rotatedin a clockwise direction and the reflectors of the lower group are rotated in a counter clockwise direction. Assuming that the pedal 17 has 'been fully depressed the reflectors are thus adjusted into the fully closed position with the respective apertures "closed. The reflect ng surfaces 54 of the reflectors in comb nation With the reflecting surface otthe fixed Walls of the casing 15 serve to reflect the energy of the compressional Waves produced by the strings back to the strings and sounding board to cause a reflex or regenerating action. The vibration effectively of the strings and sounding board is thus sustained for ,a considerable period. I s h p WVhen it is desired to emit at least a portion of the sound produced within the resonatingchambers within the casing 15 the pedal 17 is raised somewhat and this motion is communicated t-o the reflectors 53 causing them to be partially opened. By raising the "pedal to a desired degreeany desired volume of sound up to the maximum mafybe 0b- The invenee'n upon v vhich this application is based is broader than the specific embodiment sho wn and described for the purpose of illustrating at least one or the Ways in which it may be employed. The scope of the invention is therefore to be understood as not being limited by the present specific de scripti'on. I intend'no limitations other than those imposed by the claims.

What is claimed is:

1 modulating system tor a pianoforte, comprising a tone modulating sedate plus rallity of modulating reflectors each p'ivota lly m imte len i a er s to weary contro'llingthe volume of sound emitted from the instrument, said reflectors benign-ran ed in tivo groups, and nians operati'vely interconnecting said pedal and said grou ps'o'i reflec'tors so that "the iveiglit of'the refitted-S counterbalance each other by grtiups, tordperating the reflectors v I I p v H "2. 'A modu'latingsystem for a pianofo'rte comprising plurality of modiilating reflectors arranged in groups, the reflectors of certain of said groupshe'ing pivotally inounted on their lateral edges respctively to reflectsound in a. predetermined direction, the reflectors of others of said groups being mounted on their lateral 'edg'esrespectiyely to counterbalance the weight (if the'refl'c'tors of the firstnained group, and a single control device for operating all of said reflectors.

3. A modulating system for api'anotorte, omprisin a pair of'restinating hambers, each having a cdntiolltblegpertu e, atone modulating "pedal, a plurality of modulating reflectors reread; of said apertureseaehef 4. A modulating system for fpianofo i'tes,

comprising acasingymeans Withinthe casing tor producing damped compressional waves,

said casing havingopp'ositely disposedcon- "troll-able"apertures for the emission of sound,

a plurality of modulating reflectors fdr hire of the apertures and pivotallymounted on their lateraledges respectively to rotate in one direction of'rotation to open therespective aperture, a second plurality orjniofdmating. reflectors it'or the bther aperture and pivot-ally mounted on their lateral edges respectively to'rotate in the oppbsite direction of rotation to open the r'espectiiieaperture, and means'for 'actuating all or said reflectors.

5. In a sound produoihg iiistruinent, a eashaving openiifgsa soureefof' soifiid vvith in said casing, "a plurality ofseparateclbsure devices for said openings, means for supporting said devices so that the weight or some balances the others, and means for operating said devices.

6. In a sound producing instrument, a casing having openings, a source of damped vibrations Within said casing, a plurality of separate closure devices for said openings, means for supporting said devices so that the weight of some balances the others, and means for operating said devices, said devices operating to reflect the sound.

7. In a sound producing instrument, a casing having a sounding board dividing said casing into two chambers, each chamber having an opening, a source of sound within said casing, a closure device for each of said openings, means for supporting said devices so that the weight of one balances the other, and means for operating said devices 8. In a sound producing instrument, a casing having a sounding board dividing said casing into tWo chambers, each chamher having an opening, a source of damped vibrations within said casing, a closure device' for each of said openings, means for supporting said devices so that the weight of one balances the other, and means for operating said devices.

9. In a pianoforte, a casing having oppositely disposed openings, a source of damped vibrations within said casing, aplurality of modulating reflectors for said openings each pivoted at one edge, and means for mounting said reflectors so that those for one of said openings balances the others, and means for opening and closing said reflectors simultaneously.

10. In a sound producing instrument, a casing having openings, a source of sound within said casing, closure devices for said openings, means for supporting said devices so that the Weights thereof balance each other, and means for operating said devices.

11. In a sound producing instrument, a casing having openings, a source of sound within said casing, a plurality of separate closure devices of ponderable mass for said openings, means for supporting said devices so that some of the weight thereof balances the remainder, and means for adjusting said devices to control the means of opening.

Signed at Gloucester, in the county of Essex and State of Massachusetts, this twenty-second day of December, A. D. 1925.

JOHN HAYS HAMMOND, JR. 

